Thanks Tom... On Wed, Jul 27, 2016 at 6:27 PM, Tom Santero <tsant...@gmail.com> wrote:
> Vikram, > > I apologize, I initially just skimmed your question and thought you were > asking something entirely different. > > While increasing your N value is safe, decreasing it on a bucket with > pre-existing data, as you have, is not-recommended and the source of your > inconsistent results. > > Tom > > On Wed, Jul 27, 2016 at 4:18 PM, Vikram Lalit <vikramla...@gmail.com> > wrote: > >> Thanks Tom... Yes I did read that but I couldn't deduce the outcome if n >> is decreased. John talks about data loss, but am actually observing a >> different result... perhaps am missing something! >> >> >> On Wed, Jul 27, 2016 at 6:11 PM, Tom Santero <tsant...@gmail.com> wrote: >> >>> Vikram, >>> >>> John Daily wrote a fantastic blog series that places your question in >>> context and then answers it. >>> >>> >>> http://basho.com/posts/technical/understanding-riaks-configurable-behaviors-part-1/ >>> >>> Tom >>> >>> On Wed, Jul 27, 2016 at 4:07 PM, Vikram Lalit <vikramla...@gmail.com> >>> wrote: >>> >>>> Hi - I have a Riak node with n_val=3, r=2, w=2 and have just one >>>> key-object stored there-in. I'm trying to test various configurations to >>>> better understand the system and have the following observations - some >>>> dont seem to align with my understanding so far, so appreciate if someone >>>> can throw some light please... Thanks! >>>> >>>> 1. n=3, r=2, w=2: Base state, 1 key-value pair. >>>> >>>> 2. Change to n=2, r=2, w=2: When I query from my client, I randomly see >>>> 1 or 2 values being fetched. In fact, the number of keys fetched is 1 or 2, >>>> randomly changing each time the client queries the db. Ideally, I would >>>> have expected that if we reduce the n_val, there would be data loss from >>>> one of the vnodes. And that for this scenario, I would still expect only 1 >>>> (remaining) key-value pair to be read from the remaining two vnodes that >>>> has the data. Note that I dont intend to make such a change in production >>>> as cognizant of the recommendation to never decrease the value of n, but >>>> have done so only to test out the details. >>>> >>>> 3. Then change to n=2, r=1, w=1: I get the same alternating result as >>>> above, i.e. 1 or 2 values being fetched. >>>> >>>> 4. Then change to n=1, r=1, w=1: I get 3 key-value pairs, all >>>> identical, from the database. Again, are these all siblings? >>>> >>>> _______________________________________________ >>>> riak-users mailing list >>>> riak-users@lists.basho.com >>>> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com >>>> >>>> >>> >> >
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